Resolving the Phylogeny of the Olive Family (Oleaceae): Confronting Information from Organellar and Nuclear Genomes.

The olive family, Oleaceae, is a group of woody plants comprising 28 genera and ca. 700 species, distributed on all continents (except Antarctica) in both temperate and tropical environments. It includes several genera of major economic and ecological importance such as olives, ash trees, jasmines, forsythias, osmanthuses, privets and lilacs. The natural history of the group is not completely understood yet, but its diversification seems to be associated with polyploidisation events and the evolution of various reproductive and dispersal strategies. In addition, some taxonomical issues still need to be resolved, particularly in the paleopolyploid tribe Oleeae. Reconstructing a robust phylogenetic hypothesis is thus an important step toward a better comprehension of Oleaceae's diversity. Here, we reconstructed phylogenies of the olive family using 80 plastid coding sequences, 37 mitochondrial genes, the complete nuclear ribosomal cluster and a small multigene family encoding phytochromes (phyB and phyE) of 61 representative species. Tribes and subtribes were strongly supported by all phylogenetic reconstructions, while a few Oleeae genera are still polyphyletic (Chionanthus, Olea, Osmanthus, Nestegis) or paraphyletic (Schrebera, Syringa). Some phylogenetic relationships among tribes remain poorly resolved with conflicts between topologies reconstructed from different genomic regions. The use of nuclear data remains an important challenge especially in a group with ploidy changes (both paleo- and neo-polyploids). This work provides new genomic datasets that will assist the study of the biogeography and taxonomy of the whole Oleaceae.

Floral volatiles identification and molecular differentiation of Osmanthus fragrans by neutral desorption extractive atmospheric pressure chemical ionization mass spectrometry.

RATIONALE: Floral volatiles are commonly present only at trace amounts and can be degraded or lost during vapor collection, which is often challenging from the analytical standpoint. Osmanthus fragrans Lour. is a widely cultivated plant known for the highly distinct fragrance of its flowers. The identification of specific volatile organic compounds (VOCs) and molecular differentiation of O. fragrans without any chemical pretreatment and VOC collection are important. METHODS: Twenty-eight VOCs released by the flowers from ten different cultivars of O. fragrans were identified using neutral desorption extractive atmospheric pressure chemical ionization mass spectrometry (ND-EAPCI-MS) without any chemical pretreatment or VOC collection. Chemical identification was performed by high-resolution MSn analysis and whenever possible was confirmed by the analysis of standards. RESULTS: According to our literature search, nine of the identified VOCs, 3-buten-2-one, cyclohexadiene, 2-methylfuran, 3-allylcyclohexene, cuminyl alcohol, hotrienol oxide, epoxy-linalool oxide, N-(2-hydroxyethyl) octanamide, and 3-hydroxy-dihydro-ß-ionone, have not been reported in O. fragrans in earlier studies. Confident differentiation between ten different cultivars of O. fragrans was achieved by the principal component analysis of the mass spectrometric results. CONCLUSIONS: The results of our ND-EAPCI-MS analysis substantially increase our knowledge about the chemistry of the O. fragrans floral fragrance and demonstrate the power of this technique for direct molecular profiling for plant recognition or in biotechnological applications.

The phylogeny and biogeographic history of ashes (fraxinus, oleaceae) highlight the roles of migration and vicariance in the diversification of temperate trees.

The cosmopolitan genus Fraxinus, which comprises about 40 species of temperate trees and shrubs occupying various habitats in the Northern Hemisphere, represents a useful model to study speciation in long-lived angiosperms. We used nuclear external transcribed spacers (nETS), phantastica gene sequences, and two chloroplast loci (trnH-psbA and rpl32-trnL) in combination with previously published and newly obtained nITS sequences to produce a time-calibrated multi-locus phylogeny of the genus. We then inferred the biogeographic history and evolution of floral morphology. An early dispersal event could be inferred from North America to Asia during the Oligocene, leading to the diversification of the section Melioides sensus lato. Another intercontinental dispersal originating from the Eurasian section of Fraxinus could be dated from the Miocene and resulted in the speciation of F. nigra in North America. In addition, vicariance was inferred to account for the distribution of the other Old World species (sections Sciadanthus, Fraxinus and Ornus). Geographic speciation likely involving dispersal and vicariance could also be inferred from the phylogenetic grouping of geographically close taxa. Molecular dating suggested that the initial divergence of the taxonomical sections occurred during the middle and late Eocene and Oligocene periods, whereas diversification within sections occurred mostly during the late Oligocene and Miocene, which is consistent with the climate warming and accompanying large distributional changes observed during these periods. These various results underline the importance of dispersal and vicariance in promoting geographic speciation and diversification in Fraxinus. Similarities in life history, reproductive and demographic attributes as well as geographical distribution patterns suggest that many other temperate trees should exhibit similar speciation patterns. On the other hand, the observed parallel evolution and reversions in floral morphology would imply a major influence of environmental pressure. The phylogeny obtained and its biogeographical implications should facilitate future studies on the evolution of complex adaptive characters, such as habitat preference, and their possible roles in promoting divergent evolution in trees.

Intricate patterns of phylogenetic relationships in the olive family as inferred from multi-locus plastid and nuclear DNA sequence analyses: a close-up on Chionanthus and Noronhia (Oleaceae).

Noronhia represents the most successful radiation of the olive family (Oleaceae) in Madagascar with more than 40 named endemic species distributed in all ecoregions from sea level to high mountains. Its position within the subtribe Oleinae has, however, been largely unresolved and its evolutionary history has remained unexplored. In this study, we generated a dataset of plastid (trnL-F, trnT-L, trnS-G, trnK-matK) and nuclear (internal transcribed spacer [ITS]) DNA sequences to infer phylogenetic relationships within Oleinae and to examine evolutionary patterns within Noronhia. Our sample included most species of Noronhia and representatives of the ten other extant genera within the subtribe with an emphasis on Chionanthus. Bayesian inferences and maximum likelihood analyses of plastid and nuclear data indicated several instances of paraphyly and polyphyly within Oleinae, with some geographic signal. Both plastid and ITS data showed a polyphyletic Noronhia that included Indian Ocean species of Chionanthus. They also found close relationships between Noronhia and African Chionanthus. However, the plastid data showed little clear differentiation between Noronhia and the African Chionanthus whereas relationships suggested by the nuclear ITS data were more consistent with taxonomy and geography. We used molecular dating to discriminate between hybridization and lineage sorting/gene duplication as alternative explanations for these topological discordances and to infer the biogeographic history of Noronhia. Hybridization between African Chionanthus and Noronhia could not be ruled out. However, Noronhia has long been established in Madagascar after a likely Cenozoic dispersal from Africa, suggesting any hybridization between representatives of African and Malagasy taxa was ancient. In any case, the African and Indian Ocean Chionanthus and Noronhia together formed a strongly supported monophyletic clade distinct and distant from other Chionanthus, which calls for a revised and more conservative taxonomy for this group.

Assessment of genetic diversity and relationships among osmanthus fragrans cultivars using AFLP markers

This study was conducted to reveal genetic diversity among 100 Osmanthus fragrans cultivars using amplified fragment length polymorphism (AFLP) markers. Eight AFLP primer combinations produced a total of 443 polymorphic fragments with an average of 64 per primer combination. The percentage of polymorphic bands (86.81 percent), the resolving power (Rp) (32.71) and the PIC values (0.331) showed the efficiency of used primer combinations. The revealed AFLP makers were effective in distinguishing all the cultivars considered. Cluster analysis were performed to assess patterns of diversity among cultivars and showed the abundant genetic diversity. The overall distribution pattern of molecular variation suggested that 93.33 percent of the total genetic variance was within the identified groups and 6.67 percent of the genetic variation was among the identified groups. Our results showed that AFLP markers are useful for Osmanthus fragrans germplasm discrimination as well as for investigation of genetic diversity and variation. The information will facilitate germplasm identification, conservation and new cultivar development.

Phylogenetics of Olea (Oleaceae) based on plastid and nuclear ribosomal DNA sequences: tertiary climatic shifts and lineage differentiation times.

BACKGROUND AND AIMS: The genus Olea (Oleaceae) includes approx. 40 taxa of evergreen shrubs and trees classified in three subgenera, Olea, Paniculatae and Tetrapilus, the first of which has two sections (Olea and Ligustroides). Olive trees (the O. europaea complex) have been the subject of intensive research, whereas little is known about the phylogenetic relationships among the other species. To clarify the biogeographical history of this group, a molecular analysis of Olea and related genera of Oleaceae is thus necessary. METHODS: A phylogeny was built of Olea and related genera based on sequences of the nuclear ribosomal internal transcribed spacer-1 and four plastid regions. Lineage divergence and the evolution of abaxial peltate scales, the latter character linked to drought adaptation, were dated using a Bayesian method. KEY RESULTS: Olea is polyphyletic, with O. ambrensis and subgenus Tetrapilus not sharing a most recent common ancestor with the main Olea clade. Partial incongruence between nuclear and plastid phylogenetic reconstructions suggests a reticulation process in the evolution of subgenus Olea. Estimates of divergence times for major groups of Olea during the Tertiary were obtained. CONCLUSIONS: This study indicates the necessity of revising current taxonomic boundaries in Olea. The results also suggest that main lines of evolution were promoted by major Tertiary climatic shifts: (1) the split between subgenera Olea and Paniculatae appears to have taken place at the Miocene-Oligocene boundary; (2) the separation of sections Ligustroides and Olea may have occurred during the Early Miocene following the Mi-1 glaciation; and (3) the diversification within these sections (and the origin of dense abaxial indumentum in section Olea) was concomitant with the aridification of Africa in the Late Miocene.

Gene relocations within chloroplast genomes of Jasminum and Menodora (Oleaceae) are due to multiple, overlapping inversions.

The chloroplast (cp) DNA sequence of Jasminum nudiflorum (Oleaceae-Jasmineae) is completed and compared with the large single-copy region sequences from 6 related species. The cp genomes of the tribe Jasmineae (Jasminum and Menodora) show several distinctive rearrangements, including inversions, gene duplications, insertions, inverted repeat expansions, and gene and intron losses. The ycf4-psaI region in Jasminum section Primulina was relocated as a result of 2 overlapping inversions of 21,169 and 18,414 bp. The 1st, larger inversion is shared by all members of the Jasmineae indicating that it occurred in the common ancestor of the tribe. Similar rearrangements were also identified in the cp genome of Menodora. In this case, 2 fragments including ycf4 and rps4-trnS-ycf3 genes were moved by 2 additional inversions of 14 and 59 kb that are unique to Menodora. Other rearrangements in the Oleaceae are confined to certain regions of the Jasminum and Menodora cp genomes, including the presence of highly repeated sequences and duplications of coding and noncoding sequences that are inserted into clpP and between rbcL and psaI. These insertions are correlated with the loss of 2 introns in clpP and a serial loss of segments of accD. The loss of the accD gene and clpP introns in both the monocot family Poaceae and the eudicot family Oleaceae are clearly independent evolutionary events. However, their genome organization is surprisingly similar despite the distant relationship of these 2 angiosperm families.

An investigation of the seasonal pattern of mannitol content in deciduous and evergreen species of the oleaceae growing in northern Sicily.

In several species of the Oleaceae, mannitol, already present at considerable levels, accumulates in response to stress. This family comprises both deciduous and evergreen species, and we investigated the role of mannitol in deciduous malacophyll and evergreen sclerophyll species growing under the same conditions in the field. The relationship between mannitol content and changes in rainfall or temperature was also studied. The mannitol content of leaves of Fraxinus ornus L., F. angustifolia Vahl., Olea europaea L. and Phillyrea media L. was determined by gas chromatography. Leaf samples were collected once a month for 1 year. In the two ash species, the seasonal pattern of mannitol content appeared the same: a gradual increase in spring, peaking in summer, followed by a gradual decrease. The mannitol content was similar in both species, ranging between 260 and 720 micromol g(-1) d. wt. The seasonal pattern of mannitol content in Olea and Phillyrea was similar for both species, but unlike that of Fraxinus did not show a summer peak. Rainfall was negatively correlated with the seasonal increase of mannitol content in ash. Mannitol content increased gradually during drought, reaching a maximum value at the end of the dry season. Temperature did not have a direct influence on mannitol content. In Olea and Phillyrea, variations in mannitol content were poorly correlated with rainfall or temperature, indicating that mannitol does not have a primary role in the response of these species to the hot, dry summer conditions.

Chemotaxonomy of the Oleaceae: iridoids as taxonomic markers.

The distribution and biosynthesis of iridoid glucosides in the Oleaceae is reviewed and five distinct biosynthetic pathways to iridoids have been identified in the family, deoxyloganic acid apparently being a common intermediate. Likewise, the distributions of caffeoyl phenylethanoid glycosides (CPGs), i.e. verbascoside and its analogues, as well as cornoside are listed. Iridoid glucoside data exist for 17 genera of Oleaceae and the occurrence of iridoids from the different biosynthetic pathways correlate extremely well with the phylogenetic classification inferred from recent chloroplast DNA sequence data. Thus the tribe Fontanesieae (Fontanesia) contains "normal" secoiridoids, Forsythieae (Abeliophyllum, Forsythia) contains cornoside and/or iridoids from the forsythide pathway, Myxopyreae (Myxopyrum, Nyctanthes) have iridoids from the myxopyroside pathway, and finally, the two tribes Jasmineae and Oleeae (the remaining genera) both contain iridoids from the oleoside pathway. Within Jasmineae, one group of Jasminum sp. is characterized by the presence of jasminin or similar compounds, while another group of Jasminum species and Menodora display derivatives of 10-hydroxyoleoside, compounds not present in the other group. CPGs are reported from about half of the species investigated. With regard to taxonomy at the order level, the chemical data might support a position within or close to Lamiales due to the common presence of CPGs, the iridoids being of less significance since they are of a type that are barely found elsewhere.

Chemical authentication of extra virgin olive oil varieties by supervised chemometric procedures.

This work has focused on discriminating extra virgin olive oils from Sabina (Lazio, Italy) by olive fruit variety (cultivar). A set of oils from five of the most widespread cultivars (Carboncella, Frantoio, Leccino, Moraiolo, and Pendolino) in this geographical area was analyzed for chemical composition using only the Official Analytical Methods, recognized for the quality control and commercial classification of this product. The obtained data set was converted into a computer-compatible format, and principal component analysis (PCA) and a method based on the Fisher F ratio were used to reduce the number of variables without a significant loss of chemical information. Then, to differentiate these samples, two supervised chemometric procedures were applied to process the experimental data: linear discriminant analysis (LDA) and artificial neural network (ANN) using the back-propagation algorithm. It was found that both of these techniques were able to generalize and correctly predict all of the samples in the test set. However, these results were obtained using 10 variables for LDA and 6 (the major fatty acid percentages, determined by a single gas chromatogram) for ANN, which, in this case, appears to provide a better prediction ability and a simpler chemical analysis. Finally, it is pointed out that, to achieve the correct authentication of all samples, the selected training set must be representative of the whole data set.